Transfer of CO 2 in an aerated microalgal culture system has been studied. The CO 2 absorption rate was not visibly affected by the kinetics of the reactions occurring in the culture medium. Biomass concentration in the bioreactor, within the interval studied, did not significantly affect the overall volumetric coefficient of CO 2 transfer (K 1a (CO 2 )). An expression has been proposed for the estimation of K 1a (CO 2 ) in the culture as a function of the effective power input to dispersion. Several empirical equations, found in the literature for estimation of the mass transfer parameters, were studied and those which best predicted experimental results are presented.

Gas‐liquid transfer of atmospheric CO2 in microalgal cultures

The accurate determination of the diffusion coefficient of dissolved CO2 in aqueous solutions is a key parameter to predict the transport of the dissolved gas in the aqueous solution of porous aquifers and caprocks in the context of the mitigation of greenhouse gases emissions. A better understanding of the diffusion kinetics of dissolved CO2 as a function of subsurface conditions is essential to ensure the integrity of CO2 storage in saline aquifers. Experimental data are available to predict the CO2 diffusion kinetics as a function of temperature and pressure. However, the impact of salinity on CO2 diffusivity is still poorly documented. In this work, the diffusion coefficients of dissolved CO2 were determined using in situ Raman microspectrometry in Fused Silica Capillaries in a range of salinity from 0.0 to 6.0mol(NaCl)kg(H2O)(-1). The diffusion coefficient of CO2 dissolved in pure water at 21 +/- 1 degrees C and 40bar is 1.71x10(-9)+/- 0.06m(2)s(-1). In the same conditions of pressure and temperature, the diffusion coefficient of dissolved CO2 decreases with salinity increase: from 0.0 to 6.0mol(NaCl)kg(H2O)(-1) (the diffusion kinetics of dissolved CO2 is divided by two). Consequently, the impact of salinity on the diffusion coefficient of dissolved CO2 must be taken into account to evaluate the transport of dissolved gases in the brine of the reservoir and caprock.

Experimental determination of CO2 diffusion coefficient in aqueous solutions under pressure at room temperature via Raman spectroscopy: impact of salinity (NaCl)

Gas–liquid flow mass transfer in a T-shape microreactor stimulated with 1.7 MHz ultrasound waves

The density, viscosity, and surface tension of 0.5 M sodium carbonate + 0.5 M sodium bicarbonate buffer solutions in the presence of glycerin, glucose, or sucrose were measured at temperatures from 25 °C to 40 °C. The concentration ranges were (0−187.2) g·dm-3 for glycerin, (0−264) g·dm-3 for glucose, and (0−204) g·dm-3 for sucrose. The experimental values were correlated with the concentration of the organic component. The maximum deviations were always less than 0.5%.

Density, Viscosity, and Surface Tension of Sodium Carbonate + Sodium Bicarbonate Buffer Solutions in the Presence of Glycerine, Glucose, and Sucrose from 25 to 40 °C

H. Kitajima

Papers

Diffusivities of carbon dioxide in aqueous mixed electrolyte solutions